The present invention relates to novel compounds which are protein kinase C inhibitors, methods for their preparation, intermediates therefor and pharmaceutical compositions comprising them.
Protein kinase C (PKC) is a family of phospholipid-dependent serine/threonine-specific protein kinases which play an important role in cellular growth control, regulation and differentiation.
Since the activation of PKC has been implicated in several human disease processes, including various forms of cancer, different forms of inflammatory and/or immunological disorders as well as some neurological disorders, inhibition of PKC could be of therapeutic value in treating these conditions.
Several classes of compounds have been identified as PKC inhibitors, e.g. isoquinoline sulphonamides, sphingosine and related sphingolipids, indolocarbazoles and bisindolylmaleimides.
Although PKC inhibitors are described in the prior art, there is a need for specific anti-inflammatory and immunosuppressive compounds which are suitable for oral administration, and for inhalation.
The present invention provides PKC inhibitors, methods for their preparation and intermediates used for their preparation.
The present invention also provides the use of the compounds of the present invention for the treatment of inflammatory, immunological, bronchopulmonary, cardiovascular, oncological or CNS-degenerative disorders.
Also provided by the present invention are pharmaceutical compositions comprising a compound according to the present invention, as active ingredient, together with a pharmaceutically acceptable adjuvant, diluent or carrier.
The present invention provides optionally substituted and/or annulated compounds of formula (I): 
wherein:
one of: R1 and R2, R2 and R3 or R3 and R4, together form a 5 or 6 membered ring and the two groups of R1, R2, R3 and R4 not forming a ring, are H;
and salts thereof.
More specifically, the present invention provides optionally substituted and/or annulated compounds of formula (I), with the proviso that 3-[3-(3-Oxo-3,4-dihydro-benzo[g]quinoxalin-2-yl)-indol-1-yl]-propyl ammonium acetate is excluded from the compounds of formula (I).
Salts of the compounds according to the invention are preferably pharmaceutically acceptable salts. Other, non-pharmaceutically acceptable salts may be useful as intermediates e.g. in the preparation of pharmaceutically acceptable salts or other compound of the present invention.
Included within the scope of the present invention are all enol tautomers of compounds of the present invention.
Preferred compounds of formula (I) are those of formula (II): 
wherein:
one of: R1 and R2, R2 and R3 or R3 and R4, together form a 5 or 6 membered ring and the two groups of R1, R2, R3 and R4 not forming a ring, are H;
R5 is H, C1-6 alkyl, hydroxyC1-6 alkyl, aminoC1-6 alkyl, (aminoC1-3 alkylphenyl)C1-3 alkyl, amidinothioC1-6 alkyl, (aminoC1-3 alkylpyridyl)C1-3alkyl;
R6 is H, C1-6 alkyl, phenylC1-6 alkyl, (C1-6 alkoxycarbonyl)C1-6 alkyl;
R7 and R8 is each independently H, dibenzylamino, nitro, hydroxy, halogen, C1-6 alkoxy, phenylC1-6alkoxy, C1-6 alkyl or carboxyC1-6 alkyl ester; or when R7 and R8 are adjacent they may together form amethylenedioxy;
R9 is H, C1-6 alkyl, phenyl, halophenyl, or benzyl and wherein when R5 and R9 together comprise 3-5 carbons they may be linked to generate a cyclic moiety which may be aminoC1-6 alkyl substituted;
and salts thereof.
Compounds of formula (II), in which R5 carries an amino or hydroxy group; and pharmaceutically acceptable salts thereof, may be prepared by,
a) deprotecting a compound of formula (III) corresponding to formula (II) but in which R5 carries a protected amino or hydroxy group, or
b) converting:
i) a compound of formula (II), in which R5 carries an amino group to a salt, preferably a pharmaceutically acceptable salt thereof, or vice versa; or
ii) a salt, preferably a pharmaceutically acceptable salt of a compound of formula (II) into a different pharmaceutically acceptable salt.
Compounds of formula (II), in which R6 is hydrogen, may be prepared by reacting a compound of formula (IV): 
wherein,
R5, R7, R8, and R9 are as defined in formula (II) and LG is a leaving group, e.g.: 
xe2x80x83with a compound of formula (V): 
xe2x80x83wherein,
one of: R1 and R2, R2 and R3 or R3 and R4, together form a 5 or 6 membered ring and the two groups of R1, R2, R3 and R4 not forming a ring, are H; conveniently in a solvent, e.g. tetrandrofuran (THF), at about 10-30xc2x0 C., e.g. for about 16 hours.
When R5 in formula (IV) carries an amino or hydroxy group, these groups are preferably protected. The protecting groups may be removed in a subsequent deprotecting step.
Compounds of formula (II), when R6 is other than H, may be prepared by reacting a compound of formula (III) which corresponds to formula (II), but in which R6 is H, with an alkylating agent in the presence of a base, e.g. sodium hydride. The alkylating step may be carried out in a suitable solvent e.g. dimethyl formamide at about 10-30xc2x0 C. for e.g. 2 hours.
When R5 in formula (III) carries an amino or hydroxy group, such groups are preferably protected. The protecting groups may be removed in a subsequent deprotecting step.
Compounds of formula (III) may be prepared by reacting a compound of formula (IV), as defined above, with a compound of formula (V), as defined above, in a solvent e.g. THF, at about 10-30xc2x0 C., e.g. for 16 h ,or when R5 in formula (IV) carries an amino or hydroxy group, these are preferably in a protected form.
In all processes above, the protecting groups and conditions for deprotection are well known to those skilled in the art. Suitable protecting groups for amino groups include e.g. phthaloyl groups and the deprotecting agent may be methylamine in e.g. water. The deprotecting step may be carried out in a solvent, e.g. THF at about 10-30xc2x0 C., e.g. for about 5 hours. The hydroxy groups may be protected as their corresponding acetoxy groups and the deprotecting agent may be methylamine in e.g. water. The deprotecting step may be carried out in a suitable solvent, e.g. tetrahydrofuran at about 10-30xc2x0 C., e.g. for about 16 hours.
In process b) the conversion may be carried out analogously to conventional processes, e.g.
i) reaction of a free base with an acid containing the desired anion, or by careful basification of the salt, or
ii) reaction of a free acid with a base containing the desired cation, or by careful acidification of the salt.
The reaction may be carried out in a solvent, e.g. methanol ormethylene chloride.
Compounds of formula (I) which are not of formula (II) may be made by analogous processes to those described above for compounds of formula (II).
Compounds of formula (I), which are not of formula (II), carrying functional groups which might be sensitive to or interfere with the reaction conditions in the above processes, may be made by analogous processes to those described above for compounds of formula (II), but in which the functional groups are protected, followed by subsequent deprotection.
When a compounds of the present invention are synthesised as regiochemical mixtures, such mixtures may be separated by techniques well known to those skilled in the art.
Functional groups that might be sensitive for or interfere with the reaction conditions in the above processes, as well as suitable protecting groups and deprotecting methods, are evident to those skilled in the art.
Starting materials for the above processes may be made by the methods as illustrated in the Examples set out belowor by methods analogous thereto. Other methods for making the starting materials will be evident to those skilled in the art.
Compounds of formula (I) and pharmaceutically acceptable salts thereof, are useful because they demonstrate pharmacological activity. In particular they demonstrate activity as kinase inhibitors, especially PKC inhibitors, e.g. as is shown by their activity in the in vitro assays described in Granet, R. A. et al, Analyt. Biochem. 1987; 163, 458-463; Olsson, H. et al, Cell Signal 1989, 1, 405-410; Chakravarthy, B. R. et al, Analyt. Biochem. 1991, 196, 144-150 and Bergstrand, H et al, J. Pharm. Exp. Ther. 1992; 263(3), 1334-1346.
In appropriate cellular systems, compounds of formula (I) and pharmaceutical acceptable salts thereof, can also reduce the generation of inflammatory mediators. For example, the compounds can inhibit oxygen radical generation and generation of pro-inflammatory cytokines in monocytes. The compounds are especially useful as inhibitors of one or more cytokines selected from IL-1xcex2, TNF-xcex1, GM-CSF or IL-8.
The compounds of the invention are indicated for use in medical therapy. More particularly, the compounds of the invention are indicated for use in the treatment of inflammatory, immunological, bronchopulmonary, cardiovascular, oncological or CNS-degenerative disorders. Preferably for oral or topical treatment of inflammatory and/or immunological disorders, such as the oral or topical treatment of airway diseases involving inflammatory conditions, e.g. asthma, bronchitis or atopic diseases, e.g. rhinitis or atopic dermatitis; inflammatory bowel diseases, e.g. Crohn""s disease or colitis; autoimmune diseases e.g. multiple sclerosis, diabetes, atherosclerosis, psoriasis, systemic lupus erythematosus or rheumatoid arthritis; malignant diseases, e.g. skin or lung cancer; HIV infections or AIDS; or for inhibiting rejection of organs/transplants.
The compounds of the invention are also indicated for use in the manufacture of a medicament for the treatment of inflammatory, immunological, bronchopulmonary, cardiovascular, oncological or CNS-degenerative disorders.
The present invention is also directed to a method for the treatment of an inflammatory, immunological, bronchopulmonary, cardiovascular, oncological or CNS-degenerative disorder, wherein a therapeutically effective amount of a compound of the invention is administered to a mammal in the need of such treatment.
The dose of the compound to be administered will depend upon the relevant indication, the age, weight and sex of the patient and may be determined by a physician. The dosage will preferably be in the range of from 0.1 mg/kg to 100 mg/kg.
The compounds may be administered topically, e.g. to the lung and/or the airways, in the form of solutions, suspensions, aerosols or dry powder formulations, e.g. formulations in the inhaler device known as the Turbuhaler(copyright); or systemically, e.g. by oral administration in the form of tablets, pills, capsules, syrups, powders or granules, or by parenteral administration, e.g. in the form of sterile parenteral solutions or suspensions, or by rectal administration, e.g. in the form of suppositories.
Compounds of the invention may be administered on their own or as a pharmaceutical composition comprising a compound of the invention in combination with a pharmaceutically acceptable diluent, adjuvant or carrier. Particularly preferred are compositions not containing material capable of causing an adverse, e.g. an allergic, reaction.
Dry powder formulations and pressurised HFA aerosols of the compounds of the invention may be administered by oral or nasal inhalation. For inhalation the compound is desirably finely divided. The finely divided compound preferably has a mass median diameter of less than 10 xcexcm, and may be suspended in a propellant mixture with the assistance of a dispersant, such as a C8-C20 fatty acid or salt thereof, (e.g. oleic acid), a bile salt, a phospholipid, an alkyl saccharide, a perfluorinated or polyethoxylated surfactant, or other pharmaceutically acceptable dispersant.
Compounds of the invention may also be administered by means of a dry powder inhaler. The inhaler may be a single or a multi dose inhaler, and may be a breath actuated dry powder inhaler.
One possibility is to mix the finely divided compound with a carrier substance, e.g. a mono-, di- or polysaccharide, a sugar alcohol, or another polyol. Suitable carriers are sugars, e.g. lactose, glucose, raffinose, melezitose, lactitol, maltitol, trehalose, sucrose, mannitol; and starch. Alternatively the finely divided compound may be coated by another substance. The powder mixture may also be dispensed into hard gelatine capsules, each containing the desired dose of the active compound.
Another possibility is to process the finely divided powder into spheres which break up during the inhalation procedure. This spheronized powder may be filled into the drug reservoir of a multidose inhaler, e.g. that known as the Turbuhaler(copyright) in which a dosing unit meters the desired dose which is then inhaled by the patient. With this system the active compound, with or without a carrier substance, is delivered to the patient.
For oral administration the active compound may be admixed with an adjuvant or a carrier, e.g. lactose, saccharose, sorbitol, mannitol; a starch, e.g. potato starch, corn starch or amylopectin; a cellulose derivative; a binder, e.g. gelatine or polyvinylpyrrolidone, and/or a lubricant, e.g. magnesium stearate, calcium stearate, polyethylene glycol, a wax, paraffin, and the like, and then compressed into tablets. If coated tablets are required, the cores, prepared as described above, may be coated with a concentrated sugar solution which may contain e.g. gum arabic, gelatine, talcum, titanium dioxide, and the like. Alternatively, the tablet may be coated with a suitable polymer dissolved in a readily volatile organic solvent.
For the preparation of soft gelatine capsules, the compound may be admixed with e.g. a vegetable oil or polyethylene glycol. Hard gelatine capsules may contain granules of the compound using either the above mentioned excipients for tablets. Also liquid or semisolid formulations of the drug may be filled into hard gelatine capsules.
Liquid preparations for oral application may be in the form of syrups or suspensions, for example solutions containing the compound, the balance being sugar and a mixture of ethanol, water, glycerol and propylene glycol. Optionally such liquid preparations may contain colouring agents, flavouring agents, saccharine and/or carboxymethylcellulose as a thickening agent or other excipients known to those skilled in art.
Compounds of the invention may also be administered in conjunction with other compounds used for the treatment of the above conditions.
The term xe2x80x98medical therapyxe2x80x99 as used herein is intended to include prophylactic, diagnostic and therapeutic regimens carried out in vivo or ex vivo on humans or other mammals.
Compounds of the present invention include all tautomers, stereoisomers, pure and mixed racemates, and mixtures thereof.
In compounds of formula (II) of the present invention, the following independent preferences apply:
R5 carries an amino group,
when R5 and R9 together form a cyclic moiety, it is preferably a six membered ring,
R2 and R3 forms a 5 or 6 membered ring,
R6 is H or alkyl and is preferably H,
any two adjacent R1, R2, R3 and R4 form an aromatic 6 membered ring, and
any two adjacent R1, R2, R3 and R4 form a heteroaromatic 5 membered ring, preferably containing 2 nitrogen atoms.
The most preferred compounds of the present invention are as follows:
3-[1-(3-Amino-propyl)-1H-indol-3-yl]-1-benzyl-1H-benzo[g]quinoxalin-2-one trifluoroacetic acid salt,
1-(3-Amino-propyl)-3-(3-oxo-3,4-dihydro-benzo[g]quinoxalin-2-yl)-1H-indole-5-carboxylic acid methyl ester acetic acid salt,
3-[1-(3-Aminomethyl-benzyl)-5-bromo-1H-indol-3-yl]-1H-benzo[g]quinoxalin-2-one acetic acid salt,
{3-[1-(3-Amino-propyl)-1H-indol-3-yl]-2-oxo-2H-benzo[g]quinoxalin-1-yl }-acetic acid methyl ester trifluoroacetic acid salt,
3-[1-(3-Amino-propyl)-1H-indol-3-yl]-1-ethyl-1H-benzo[g]quinoxalin-2-one acetic acid salt,
3-[1-(2-Amino-ethyl)-1H-indol-3-yl]-1H-benzo[g]quinoxalin-2-one acetic acid salt,
2-{3-[3-(3-Oxo-3,4-dihydro-benzo[g]quinoxalin-2-yl-indol-1-yl]-propyl}-isothiourea tris methanesufonic acid salt,
3-[1-(3-Aminomethyl-benzyl)-1H-indol-3-yl]-1,6,7,8-tetrahydro-cyclopenta[g]quinoxalin-2-one acetic acid salt,
7-[1-(3-Amino-propyl)-1H-indol-3-yl]-1,5-dihydro-1,2,5,8-tetraaza-cyclopenta[b]naphthalen-6-one acetic acid salt,
7-[1-(3-Amino-propyl)-5-bromo-1H-indol-3-yl]-1,5-dihydro-1,2,5,8-tetraaza-cyclopenta[b]naphthalen-6-one acetic acid salt,
7-[1-(3-Amino-propyl)-5-benzyloxy-1H-indol-3-yl]-1,5-dihydro-1,2,5,8-tetraaza-cyclopenta[b]naphthalen-6-one acetic acid salt,
7-[1-(3-Amino-propyl)-5-bromo-1H-indol-3-yl]-2,3-dihydro-5H-1,4-dioxa-5,8-diaza-anthracen-6-one acetic acid salt,
2-[1-(4Amino-butyl)-1H-indol-3-yl]-4H-benzo[f]quinoxalin-3-one acetic acid salt,
2-[1-(3-Aminomethyl-benzyl)-1H-indol-3-yl]-4H-benzo[f]quinoxalin-3-one acetic acid salt,
2-[1-(3-Amino-propyl)-5-bromo-1H-indol-3-yl]-4H-benzo[f]quinoxalin-3-one acetic acid salt,
3-[1-(6-Aminomethyl-pyridin-2-ylmethyl)-1H-indol-3-yl]-6,7,8,9-tetrahydro-1H-benzo[g]quinoxalin-2-one acetic acid salt,
7-[1-(3-Amino-propyl)-2-methyl-1H-indol-3-yl]-2-hydroxy-1,5-dihydro-imidazo[4,5-g]quinoxalin-6-one acetic acid salt,
2-[1-(3-Amino-propyl)-5-methoxy-1H-indol-3-yl]-4H-benzo[f]quinoxalin-3-one acetic acid salt,
and the corresponding free amines thereof and other pharmaceutically acceptable salts thereof.